This invention relates to a method and compound for testing the integrity of a blue flame gas fired forced air furnace combustion chamber.
1. Field of the Invention
Central air conditioning units presently in use usually contain a heat exchanger which heats the air circulated through a building space during cool or cold weather. The gas fired heat exchanger acts as a furnace in an air conditioning system and includes a combustion chamber having its exterior surface in intimate contact with the return air to be heated before being moved to the building space for heating the latter. However, as a result of the expansion and contraction of metal, from which the combustion chamber is usually formed, minute cracks or pin holes develop in welds joining edges of the metal which allows carbon monoxide or other noxious fumes to enter the breathable air stream moving across the combustion chamber.
This invention provides an economical compound and easily executed method for determining whether or not the integrity of the heat exchanger cell, of the gas fired blue flame forced air furnace, has been compromised such that it allows communication between the conditioned air supply and the combustion chamber of the system.
2. Description of the Prior Art
U.S. Pat. No. 5,170,840 issued Dec. 15, 1992 to Grunwald for METHOD FOR DETECTING BREACHES IN HEAT EXCHANGER TUBING, and U.S. Pat. No. 5,357,782 issued Oct. 25, 1994 to Henry for LEAK DETECTION IN HEATING, VENTILATING AND AIR CONDITIONING SYSTEMS USING AN ENVIRONMENTALLY SAFE MATERIAL are considered good examples of the state-of-the-art. The Grunwald patent *840 requires the inner and outer surfaces of a tubing type heat exchanger to be cleaned internally by an acid aqueous solution and its outer surface similarly cleaned by the aqueous solution or mechanical means. A colored admixture is introduced into the heat exchanger for visually inspecting the exterior of the heat exchanger to determine if any of the colored admixture has seeped through cracks in the heat exchanger.
The Henry Patent *782 discloses adding a compound mixture to a refrigerant system and inspecting the system under ultraviolet light for the indication of any leakage.
This invention is believed distinctive over these and other patents by providing an economical, and easily performed method of detecting leaks in a gas fired heat exchanger while the unit is in operation by adding a mist of a solution, containing a fire retardant, into a heat exchanger by air pressure differential which discolors the normal blue flame of a gas fired heat exchanger to indicate that the heat exchanger cell has been compromised.